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Discussion Starter #1
I've been talking to Weston a bit about injectors lately, and the subject shifted to my plans for putting some springs and pushrods in first.

hell I'll just quote him:

Smokem said:
Do yourself a favor.

http://www.summitracing.com/parts/cro-68190-24

Pushrods-Manton Pushrods-High Performance Pushrods

Smith Bros. Push Rods Bend Oregon

Both SB and Manton make the pushrods for the Cummins engine, you will want 3/8" 0.093-0.095" wall thickness, you may be surprised how much money you will save.
My question is: Has anyone tried these before with compounds? I'm not talking about winding the engine out to 4k+ rpm...my purpose will be just to hold the valves closed for ~75psi and to wrap to 3400rpm quickly without valve float.

thoughts?

I usually trust Weston's recommendations, just wondering if anyone else has tried these push rods and springs? seems like a killer deal as far as springs go...bout $200-300 cheaper than anyone else. though it looks like they are 74# installed pressure vs the typical 105# installed pressure.
 

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I don't think he would lead you astray. Try them out. Heck, the Hamilton springs I got just looked like something from the hardware store. I then traded a TC for some Manning Motorsports push rods, so I can't help much there. I think the manning rods are solid though.
 

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nice...I questioned him on it and his reply

Smokem said:
That is the spring everyone is selling, the listed installed height is 1.550" for 74lbs @ the seat, but they installed height in a Cummins head is ~ 1.400" for 110lbs @ the seat.
anyone wanna save several hundred on springs?! :thumbsup:
 
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I'd give em a shot! Problem is I won't be doing twins for about a year.... Unless a miracle happens, or my money tree starts producing more.
 

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Guess I'll be the guinea pig. just ordered them... $123.92 shipped for a full set of 24, what the hell might as well right?! :hehe: saves me $200+ over other "house brand" springs. or close to $300 savings over hamilton springs.

now for push rods...
 
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Discussion Starter #7
pushrods ordered via manton @ 3/8" .095" wall thickness

and the price for a set is:

drum roll :drum:......................................................























$127.68 for a set of 12. (before shipping costs)

best online price I could find from vendors and such was $195 before shipping for maxspools... so that saves $67 and some change :woot:
 
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Ill give it a shot, not like I have enough to really push up past 55psi but I have been needing to do springs and studs for a while. Let me know how your install goes, do you have the spring compressor?

Kody
 

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Discussion Starter #9
no...was thinkin of buyin one from Jamie.

btw stock springs are only something like 50# springs...

as I said in the original post though: I have no plans on turning 4k+rpm so I'm not doing aftermarket retainers or rockers or any of that...just the rods and springs. hell this budget setup is cheaper than a set of springs alone from most places! :D
 
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Discussion Starter #11
Nice find, I'm sure Weston wouldn't lead you a stray.


Sent from AutoGuide.com Free App
He didn't as you can see from post #3 :thumbsup:

Weston verified that they are 110# springs. I was just reading the specs on the summit site and they were 74# seated pressure @ 1.550 installed height. Cummins installed height is ~1.400 making them 110# seated pressure.

Anyway all this crap should arrive in a week or two, then I'll take some pics and attempt to get this stuff installed and re-adjust my valves.
 
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no...was thinkin of buyin one from Jamie.

btw stock springs are only something like 50# springs...

as I said in the original post though: I have no plans on turning 4k+rpm so I'm not doing aftermarket retainers or rockers or any of that...just the rods and springs. hell this budget setup is cheaper than a set of springs alone from most places! :D
Im guessing you went with the 304's?

Edit: From Hamiltoncams.com "If you are over 750hp with your ISB, the cylinder pressures dictate that you step up to our extreme duty pushrods which consist of a 3/8" .095" wall intake pushrod and a 7/16" .120" exhaust pushrod."

Someone want to give us the run down on the big differences between hard drawn, and melonite?
 

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Discussion Starter #13
yeah, they already shipped them out. :D

as for the pushrod question: I believe they are the 304 hard drawn.

I dunno. I just told dude on the phone the application, the spring pressures it will have to deal with, and the specs in the first post.

he said they should ship out by the end of the week :D
 

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As long as they can both be compressed the same before coil bind and they have basically the same spring rating once compressed then I dont think that there will be too big of an issue. However I have been wrong plenty of times. I'm with carbur8tr, the engineer in me wants to see some tests! :)
 

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Discussion Starter #16
as do I. I can see one is taller than the other. and the shorter is ever so slightly thicker.

Honestly I don't care as long as they hold at least 85# which would be more than enough to hold 75psi of boost back.

As I have stated before I have no plans of turning high rpm's...


now this isn't from real world testing, but based on the spring specs and cummins installed height vs provided install height example lets just do the math on the crower springs...


this is data provided by crower:

Valve Springs, Single, 1.090 in. Outside Diameter, 289 lbs./in. Rate
Installed Height (in): 1.550 in.
Seat Pressure at Installed Height (lbs): 74 lbs.


so from that we can determine that if our installed height is 1.550 in we should have 74# at the valve seat.

according to Weston the installed height of a cummins spring is ~1.400 so lets just use that figure..

the difference between example installed height vs cummins installed height is .150"

the spring rate is 289# per inch. So that would mean .150" would increase in pressure by 43.35# making installed seat pressure 117.35#

mathematically they are 110# + springs.

so in theory they will work to substitute the 2-3x more expensive springs.

now for real world testing: this has yet to be seen/proven. however if they perform better than stock, and well enough to hold back 75psi without valve float: good enough for me :thumbsup:
 
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Thats what I was thinking Jig

One other question I have is what is the compressed height of both at/or before binding? Other than that I think that they would be fine. The are probably made for a gas motor too that turns a few thousand rpm more than just 3,400. lol

Also what psi will 110# springs hold back? Just wondering...
 

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Discussion Starter #18
theoretically whatever seat pressure is, is whatever the valves can hold back before pushing open slightly

that does not take into account cylinder pressure at the time...

the valves are definitely not going to float on the compression stroke... just too much pressure in the cylinder holding that valve closed.
 

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so theoretically these will hold more pressure than your set up will do?

Also do you have a marine head gasket? why are those better than the stock one and when do you need one? (or is it wise to do)

just learnin...
 

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Discussion Starter #20
In theory yes. for HG, mine is a stock cummins HG that is only a few years old...it was replaced in late 2009 early 2010..
 
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